前面我们已经学习mybatis相关知识，领略了mybatis的强大。但是有没有发现mybatis的一些缺陷。在myabtis眼里无论是单表还是多表都要自己写sql语句（即使使用注解的方式），那么有没有一种方式针对单表我们可以不写sql语句呢，毕竟在项目开发中绝大多数是单表，尤其是互联网项目。
开源的力量是无穷的，针对mybatis的上述缺陷，国产大神团队开发了牛逼的Mybatis-plus，与mybatis无缝衔接，不降低mybatis的性能，而大大的增加了开发效率。
一、创建maven项目并导入相应的开发包
4.0.0
com.qiu
mybatis-plus
0.0.1-SNAPSHOT
com.baomidou
mybatis-plus
2.3.1
com.alibaba
druid
1.1.10
org.apache.velocity
velocity
1.7
junit
junit
4.12
test
org.springframework
spring-tx
4.3.3.RELEASE
org.springframework
spring-jdbc
4.3.3.RELEASE
org.slf4j
slf4j-api
1.7.25
org.freemarker
freemarker
2.3.28
mysql
mysql-connector-java
5.1.36
org.springframework
spring-aop
4.3.3.RELEASE
org.springframework
spring-webmvc
4.3.3.RELEASE
org.springframework
spring-context
4.3.3.RELEASE
org.springframework
spring-core
4.3.3.RELEASE
二、使用mybatis-plus代码生成器生成相应的代码
package generator;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.InjectionConfig;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import com.baomidou.mybatisplus.generator.config.FileOutConfig;
import com.baomidou.mybatisplus.generator.config.GlobalConfig;
import com.baomidou.mybatisplus.generator.config.PackageConfig;
import com.baomidou.mybatisplus.generator.config.StrategyConfig;
import com.baomidou.mybatisplus.generator.config.TemplateConfig;
import com.baomidou.mybatisplus.generator.config.converts.MySqlTypeConvert;
import com.baomidou.mybatisplus.generator.config.po.TableInfo;
import com.baomidou.mybatisplus.generator.config.rules.DbColumnType;
import com.baomidou.mybatisplus.generator.config.rules.DbType;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;
public class MybatisPlusGenerator {
public static void main(String[] args) {
String packageName = "com.qiu";
// user -> UserService, 为true: user -> IUserService
boolean serviceNameStartWithI = false;
generateByTables(serviceNameStartWithI, packageName, "user", "role");
}
private static void generateByTables(boolean serviceNameStartWithI, String packageName, String... tableNames) {
GlobalConfig config = new GlobalConfig();
String dbUrl = "jdbc:mysql://localhost:3306/mybatis";
DataSourceConfig dataSourceConfig = new DataSourceConfig();
dataSourceConfig.setDbType(DbType.MYSQL);
dataSourceConfig.setTypeConvert(new MySqlTypeConvert() {
// 自定义数据库表字段类型转换【可选】
@Override
public DbColumnType processTypeConvert(String fieldType) {
System.out.println("转换类型：" + fieldType);
return super.processTypeConvert(fieldType);
}
});
dataSourceConfig.setDbType(DbType.MYSQL).setUrl(dbUrl).setUsername("root").setPassword("123456")
.setDriverName("com.mysql.jdbc.Driver");
StrategyConfig strategyConfig = new StrategyConfig();
strategyConfig.setCapitalMode(true).setEntityLombokModel(false)
// .setDbColumnUnderline(true)
// 采用驼峰策略
.setNaming(NamingStrategy.underline_to_camel).setInclude(tableNames);
config.setActiveRecord(false).setAuthor("qiuzhangwei")
// 输出位置
.setOutputDir("d:\\").setFileOverride(true);
if (!serviceNameStartWithI) {
config.setServiceName("%sService");
}
new AutoGenerator().setGlobalConfig(config).setDataSource(dataSourceConfig).setStrategy(strategyConfig)
.setPackageInfo(
new PackageConfig().setParent(packageName).setController("controller").setEntity("entity"))
.execute();
}
}
三、代码生成器生成的代码
- entity
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@TableId(value = "id", type = IdType.AUTO)
private Integer id;
private String userName;
private String userPassword;
private String userEmail;
private String userInfo;
private String headImg;
private Date createTime;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserPassword() {
return userPassword;
}
public void setUserPassword(String userPassword) {
this.userPassword = userPassword;
}
public String getUserEmail() {
return userEmail;
}
public void setUserEmail(String userEmail) {
this.userEmail = userEmail;
}
public String getUserInfo() {
return userInfo;
}
public void setUserInfo(String userInfo) {
this.userInfo = userInfo;
}
public String getHeadImg() {
return headImg;
}
public void setHeadImg(String headImg) {
this.headImg = headImg;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", userName=" + userName +
", userPassword=" + userPassword +
", userEmail=" + userEmail +
", userInfo=" + userInfo +
", headImg=" + headImg +
", createTime=" + createTime +
"}";
}
}
- mapper
//这里继承BaseMapper，实现单表无sql语句
public interface UserMapper extends BaseMapper {
}
- UserMapper.xml
四、mybatis和spring相关配置
- applicationContext.xml
- mybatis-config.xml
- ab.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis
jdbc.username=root
jdbc.password=123456
- log4j.properties（打印出相应的sql语句用于调试）
五、测试
- spring资源初始化
private ApplicationContext ioc=null;
private UserMapper userMapper=null;
@Before
public void init() {
ioc=new ClassPathXmlApplicationContext("applicationContext.xml");
userMapper=ioc.getBean(UserMapper.class);
}
- 1.插入
@Test
public void insertUser() {
User user=new User();
user.setUserName("qiu1");
user.setUserPassword("111");
user.setCreateTime(new Date());
user.setUserInfo("demo1");
// insert插入数据
int insert = userMapper.insert(user);
//打印
System.out.println(user.getId());
}
- 2.修改
@Test
public void update() {
User user = new User();
user.setUserName("qiu1");
user.setUserPassword("111111111111");
user.setCreateTime(new Date());
user.setUserInfo("demo1");
user.setId(5);
int updateById = userMapper.updateById(user);
System.out.println(user.getUserPassword());
}
- 3.删除（按id删除和批量删除）
@Test
public void delete() {
//按id删除
int deleteById = userMapper.deleteById(1);
System.out.println(deleteById);
//批量删除
List list = new ArrayList();
list.add(1);
list.add(2);
list.add(5);
userMapper.deleteBatchIds(list);
}
- 4.查询
@Test
public void select() {
//1.按id查询
User user = userMapper.selectById(1);
System.out.println(user);
//2.批量查询
List list = new ArrayList();
list.add(1);
list.add(2);
list.add(5);
List selectBatchIds = userMapper.selectBatchIds(list);
selectBatchIds.forEach(System.out::println);
//3.使用JavaBean封装按条件查询
User queryUser = new User();
queryUser.setUserName("qiu1");
queryUser.setUserPassword("1111111111");
User selectOne = userMapper.selectOne(queryUser);
System.out.println(selectOne);
//4.使用map封装按条件查询
Map map = new HashMap<>();
map.put("user_name", "qiu1");
List selectByMap = userMapper.selectByMap(map);
selectByMap.forEach(System.out::println);
//5.分页查询
int current = 1;
int size = 5;
Page page = new Page<>(current, size);
List selectPage = userMapper.selectPage(page, null);
System.out.println(selectPage.size());
}
- 5.功能强大的EntityWrapper(实现灵活的动态拼接）
@Test
public void enrityWrappertets() {
EntityWrapper entityWrapper = new EntityWrapper<>();
//条件查询user_name=‘qiu1’
entityWrapper.eq("user_name", "qiu1");
//分页查询
List selectPage = userMapper.selectPage(new
Page(1, 5), entityWrapper);
selectPage.forEach(System.out::println);
}